1. Field of the Invention
The present invention relates to a keyboard apparatus which is used in musical instruments such as pianos, and relates to a keyboard instrument.
2. Description of the Related Art
In keyboard instruments such as conventional acoustic pianos, each of plural keys is provided with a mechanism which consists of a wippen which swings when a key is pressed, a jack driven in accordance with rotation of the wippen, and a hammer member driven by the jack to strike a string, as described in Japanese Unexamined Patent Publication No. 2002-258835.
In this mechanism, the keys are urged to swing upward by the total weight of the wippen, jack and hammer member, whereby the front ends of the keys are brought to the initial positions by initial loads. Therefore, the keyboard apparatus gives a player a constant initial load when he/she performs a key operation on the keyboard instrument.
But in the mechanism of the keyboard apparatus, when the weight of the hammer member is made heavier in a low-pitched tone side than in a high-pitched tone side to change a key load in performing a key operation between the low-pitched tone side and the high-pitched tone side, the key load at the initial position changes between the low-pitched tone side and the high-pitched tone side, giving the player something strange feeling when he/she plays the keyboard instrument. In the conventional acoustic piano, heavier weights are attached to the keys in the low-pitched tone side than in the high-pitched tone side, whereby the key loads of the keys in the initial positions are kept constant.
A key touch feeling similar to the key touch feeling given by the acoustic piano can be obtained with the above structure, but the additional weights to be attached on the keys already provided with the wippen, jack and hammer member will invite inconveniences including a high cost of the instrument and a complicated structure.